public function testCanComputeNonAnalytic()
{
$z = new Complex(1, 2);
$accuracy = 1.0E-9;
$this->assertEquals(sqrt(5), $z->abs(), 'abs', $accuracy);
$this->assertEquals(1, $z->r(), 'r', $accuracy);
$this->assertEquals(2, $z->i(), 'i', $accuracy);
$this->assertEquals(1.107148718, $z->arg(), 'arg', $accuracy);
}